This invention concerns a gut casing holding device for a sausage filling machine.
Various systems are known for holding the gut casing in place, whether it be natural or manufactured casing material, on the fill tube of a sausage filling machine during the filling process so as to control the plumpness of the sausage being made. These systems utilize an elastic ring or similar object to hold the casing in place. These so-called casing holders also serve to prevent the casing from sliding or twisting on the fill tube while the sausage is being pressed to fill the casing. The casing holding ring exerts a radial pressure on the casing as it passes through, at which point it is very important for the ring to be exactly centered and capable of adjusting to variances in casing quality. Even minor inequalities in centering can lead to damage to the casing.
One casing holding ring using an elastic lip and revolving at the same time as the fill tube is known from German Pat No. 1,532,033. The width of the lip of the casing holding ring is narrower than the opening radius of the fill tube, and the alignment of the ring opening for the passage of the casing occurs by means of a sideward movement of the casing holding ring relative to the fill tube. An automatic centering of the fill tube is not possible.
Another configuration of a casing holding device is set forth in German Pat. No. 1,111,530. A ring slot for the casing is situated between a cone on the end of the fill tube and an opposing concave cone. This opposing cone is mounted on a tube that surrounds the fill tube, and is situated on a diagonal section that can slide forward and backward under the inertia produced by rotation and pressing in such a manner that the ring slot closes on its own, resulting in the sausage casing being held tightly in position until the pressing is finished, at which time the ring slot opens again on its own. This device is also incapable of automatic centering.
One final casing holding device is described in German Pat. No. 2,203,695 that is radially flexible relative to the fill tube and that is axially immobile. Neither the fill tube nor the casing holding element are able to rotate. The floating mount of the casing holding element is intended to achieve automatic self-centering under all operating conditions.
The aforementioned casing holding devices all have disadvantages of one sort or another. None of them are suited for high working speeds because they place too much of a strain on the casing and do not allow enough control in gently releasing their hold on the casing. This makes their highest working speeds more dependent on the type of sausage casing used, rather than on the actual speed at which the machine is capable of operating, whether it be a filling machine, portion sizer or sausage press controller.
It is especially when dealing with fill tubes of narrow diameters and relatively minimal wall strengths that irregularities and bends can occur due to careless handling on the part of the operating personnel. The casing holding device is equipped with a floating mounted outer lip in accordance with German Pat. No. 2,203,695. But since this outer lip does not rotate, an exactly centered passage of the sausage casing between the fill tube and the outer lip is not possible, which unavoidably leads to a partial overloading of the casing, and could even lead to its rupturing under high speed operating conditions. A rotational mounting of the casing holding device according to German Pat. No. 2,203,695 would not help because this type of device is too heavy and consists of too many pieces to be suitable for a rotating construction. Its centrifugal force would be greater than the counterforce that would be generated by an out-of-round fill tube as it rotated.